Process of producing chlor-derivatives of methane



Feb. 9 1926.

. B. CARTER ET AL PROCESS OF PRODUCING CHLOR'DERIVATIVES OF METHANE Filedl August 9 1923 w l S Rmhhmmmmb KMNNN@ NSN m1 .mwmwb w Patented Feb. 9, 192e.A

UNITED STATES y 1,572,513 PATENT OFFICE.

CARNIE B. CARTER AND ALBERT E. COXE, OF PITTSBURGH, PENNSYLVANIA, AS-

SIGNORS T S. `IKARPENc BROS., OF CHICAGO, ILLINOIS, A ,CORPORATIONl 0F YIRGINIA.

p rnocnss or PnoDUcINe cHLon-Dnmvnrrvns or METHAN.'

Application led August 9, 1923. Serial No. 656,487. l

To all 'whom it may concern.:

ABe it known that we, CARNIE B. CARTER and ALBERT E. CoxE, citizens of the lUnited States, residing at Pittsburgh, in the county of Allegheny andState of Pennsylvania, have inventedA a new and useful Improvement in Processes of Producing Chlor- Derivatives of Methane, of which the following is a specification.

ltr This invention relates particularly to the production of the higher chlorides l from methane, and more especially to a process which will enable a highyield of methylene chloride to be obtained from methane and l chlorine.

The improved process can be readily and I safely carried on in a closed circuit into which chlorine and methane are continuously fed in suitable proportions, as for example 100 volumes of chlorine to about 46 volumes of methane.

In the practice of the improved process `in the preferred manner, one obtains a yield of about 80% methylene chloride (CI-I2Cl2),

about 15% chloroform (CI-ICla), and about 5% carbon tetrachloride. In the system which is employed, a mixture of methyl chloride (CHaCl) and methane (CIL) is circulated through a chlorinator, chlorine and methane Aare fed into the system in suitable proportions, and methylene chloride, chloroform and carbon tetrachloride are taken in liquid form from the system. These products are subjected to fractional distillation to effect separation.

The proportions of chlorine and methane which are fed into the system are determined by the respective yields of the higher chlorides. ,v

l The process may be conveniently described in connection with the accompanying drawing, which represents diagrammatically one form of suitable apparatus for the practice of the process.

In the drawingl A represents a mixer; B, a chlorinator; C, an acid scrubber; D, a gasometer; E, a compressor; F, a condenser; G, a receiver; H, a gasometer; I, a' circulating pump; J., a chlorine feed pipe;`K, a methane feed pipe;

L, a still; M, a storage tank which receivesthe liquid methylene chloride, chloroform and carbon tetrachloride; and N, a suitable check valve, or expansion valve. regulating the passage of gas from the receiver G to the ga'someter H.

The system through which constant circulation takes place in the preferred practice of the process includes the pipe 1 leading to the mixer A; the pipe 2 leading from the mixer to the chlorinator B; the pipe 3 leading from the chlorinator to the acid scrubber C; the pipe4 4 leading from the scrubber to the gasometer D; the pipe 5 leading from the gasometer D to the compressor E; thepipe 6 leading from the compressor to the condenser F; the pipe 7 leading fro-m the condenser to the receiver G; the pipe 8 leading from t-he receiver to t-he g'asometer` H, the pipe 8 containing the expansion valve N; the pipe 9 leading from the receiver to the still L; the pipe'lO leading from the still and communicating vthrough the pipe 8 with the gasometer H;

"the gases fed to the chlorinator B will be in about the following proportions: 100 Vols. chlorine, 100 vols. methyl chloride, 200 vols. methane.

,On the foregoing basis, the system will so operate that the pipe 11 will deliver tothe pipe 1. about 253.75 vols. of a mixture of methane and methyl chloride, this mixture .being composed of 100 vols. methyl lchloride Aand 158.75 vols. methane.

Such a mode of operation requires a feed of 100 vols. chlorine through the inlet pipe J and 46.25 Vols. methane through the inlet pipe K.

The ratio of methane to methyl chloride circulating in the system through the pipe 11, it will be noted, is approximately 60 'parts methane to 40 parts methyl chloride.

That is, the methane is about 50% greater than the methyl chloride.

The chlorinator B is of earthenware, quartz or other suitable material, which preferably is maintained at aI temperature of 400 C.

point, it is not desirable to employ a temperature in excess of 650. Any suitable means may be employed for maintaining the chlorinator at the desired temperature.

Hydrochloric acid is formed in the process, and this is removed when the gases are passed through the scrubber C. The gases contained in the gasomet'er D are the four chlorides and methane. By means of the confpressor E and the condenser F, the highyer chlorides are condenser and passed to the receiver Gr. The liquefied gases pass through the pipe 9' which is provided with a valve O, which maybe a check valve. 'I he methane and the most of the methyl chloride escape from the receiver, and passing the check valve N, enter the gasometer H. Some of the methyl chloride, and perhaps small quantities of methane, may pass into the still L. The still L is operated at a suitable temperature to` expel the methyl chloride and any entrapped methane, so thatthe same will pass into the gasometer H. The liquid methylene chloride, chloroform and carbon tetrachloride pass from the still into the storage tank M. Any suitable means mayV be employed for effecting separation of the liquefied products derived from the operation of the system.

The process described obviates the de'- struction of the methane molecule by the reaction which forms carbon and hydrochloric acid. Hence, the method may be practiced without danger of a reaction of explosive violence.` Moreover, the process enables a high yield /o' methylene chloride to be obtained in a ver simple manner. In order to secure large yields of methylene chloride, it is necessary to employ relatively 'high chlorine concentration, orto resort/to some method for the removal of methylene chloride, as it is formed, from the system. This latter course is the one adopted in the practice of the present process. Two results follow from this: First, the danger of re action of explosive violence is obviated; and second, the formation of excessive amounts of chloroform and carbon tetrachloride is avoided. This is of importance where the main product desired is methylene chloride.

In the practice of the processthe system may be considered as filled initially with a mixture of methane and methyl chloride in the ratio of about 60 parts methane to about 40 parts methyl chloride. If desired, the.

system may be filled initiallyl with methane,

and chlorine may bev fed gradually into the system until the desired mixture is obtained, the chlorinator operating to effect the chlorination of the methane until the desired proportions are obtained. The proportions of the methane and chlorine feeds will then de- `termine the relative proportion of the liquid products accumulating in the storage tank M. v

A pressure ofbetween 10 and 15 atmospheres is a suitable pressure to employ at t-he compressor.

The mixer A may be of any suitable construction. A cylinder will answer, but preferably some suitable .means is employed for effecting a more thorough mixing.

The proportions of the gases in the system may 'be varied. Thus, the gases passing through the pipe 1 may be composed of from 10 to 30% chlorine and 90% to 70% methane and methyl chloride. It is preferred, how-v ever, to employ about 25% chlorine. In the specific example given above, calculated to give a yield of about 80% methylene chloride,15'% chloroform and 5% carbon tetrachloride, the chlorine and methyl chloride are fedto the chlorinator in about equal volumes, together with the desired amount bf methane. It is preferred to use the chlorine and methyl chloride in about these proportions; and, in practice, these are about the bij proportions which will be maintained, erven x though the percentage of chlorine employed in the mixture fed to the chlorinator be changed within the limits stated in the present paragraph.

Rapid passage -of the gases through the/` chlorinator is desirable, inasmuch as the chlorine will be consumed within a few se'cy onds, at the temperatures employed.

From thedescription given, it will be understood thatwk the improved processcan be practiced in a highly satisfactory manner claims should be construed as broadly aspermissible in view of the prior art.

What we regard as new,- and desire to secure by Letters Patent, is:

1.' The process of producing the higher v `chlorination products of methane which comprises passing a mixture comprising methyl chloride, methane and chlorine through a reaction chamber maintained `at elezvated temperature, the methyl chloride and chlorine being present in approximately equal volumes.

2. The processof producing the higher chlorination products of methane which i comprises passing a mixture comprising methyl chloride, methane and chlorine through a reaction chamber maintained at a temperature between 350 C. and 650 C.,

l chlorine fed into the reaction chamber.

3. The process of producing the higher chlorination products of methane which comprises passing a mixture of methyl chloride, methane and chlorine through a lreaction chamber maintained at elevated temperature, the gases being taken in proportions of from to 30% chlorine and 70% to 90% aggregate of methyl chloride and methane the methyl chloride and chlorine being employed in approximately equal volumes.

4. The process of producing the higher chlorination products of methane which comprises passing a mixture comprising methyl chloride, methane and chlorine th-rough a reaction chamber maintained y at elevated temperature, the gases being employed in proportions of from 10 to 30% chlorineand 70 to 90% aggregate of methyl chloride and methane, the methane being 1n excess of the methyl chloride and ther latter being about equal in volume to the chlorine.

5. The process of producingthe higher chlorination products o f methane which comprises passing a mixture comprising methyl chloride, methane and chlorine through a reaction chamber maintained at a temperature between 350 C. and 650 C., removing the higher chlorination products for-med in the passage through the reaction chamber and. passing the remaining methyl chlorideand methane together with fresh supplies of chlorine and methane throu h the reaction chamber, the methyl chlori e Land chlorine being employedvin substantially equal voll urnes.

chlorination products of methane which comprises circulating a ymixture of methylchloride and methane through a circuit which includes a chlorinator, introducin Il freshl supplies of chlorine and methane into .the circuit, and removing the higher chlorination products fromv the circuit, the methyl chloride and chlorine being fed to the chlorinator in substantially equal volumes.

8. The recess of producing methylene chloride w ich comprises circulating a mix- 'ture comprising methyl chloride and methane through a closed system which includes a chlorinator, removing from the system the methylene chloride formed, and retaining the methyl chloride in the system and introducing into the system fresh supplies of chlorine and methane.

9. The recess of producing methylene chloride w ich comprises circulatinga mixture comprising 'methyl chloride and y methane through a closed system which includes a chlorinator, removin from ithe system the methylene chloride ormed, and retaining the methyl chloridefin the system and introducing into the system fresh supplies of chlorine and methane, the chlorine introduced being in excess ofthe methane.

10. The process of producing methylene chloride which comprises circulating a mixture kcomprising methyl chloride and methane throu h a closed system which includes a chill A tem the methylene chloride formed, and retaining the methyl chloride in the system and introducing into the system fresh supplies of chlorine and methane, the chlorine eing at least twice the proportion of the methane.

11. The process of producing the higher chlorination roducts of methane which comprises circu ating a mixture comprising \methyl chloride and methane through a'system which includes a chlorinator, introducing fresh supplies of chlorine and methane into said system, removing the'acid-formed, and condensing the higher -chlorination products and removin them from the system and retaining in t e system the methylchloride.

CARNIE B. CARTER.

' ALBERT E. COXE.

orinator, removing fromthe sysl' f 

